What is the meaning of height maps?

Question

I’ve been pondering this question for a long time ... many 3D engines support extended terrain using quadrants, LODs ... all the features you expect. But every engine I've seen loads height data from elevation maps ... grayscale bitmaps. I just don’t understand how useful this is: each point in the height map can have one of 256 values. But what if you want to simulate Mt. Everest? with a detail of 1 meter or more? This is far beyond the range of 256. Of course, I understand that you can implement your own terrain format to achieve this, but I just cannot understand why elevation maps are so widely used, despite their great limitations.

Answer 1

In terms of displaying graphics, the greatest accuracy that usually matters (in plain language) is the only pixel on the final display ¹ . Given the resolution of a regular current monitor, having another pair or three bits for a height map would be nice - but for most geometries this is really not necessary. In particular, although a single pixel pretty much determines the greatest accuracy for which you have many benefits, drawing Mt. Everest, so its height is actually two or three pixels incorrect, is not really a big problem for most people most of the time.

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Of course, depending on the format of the information stored in the height map, some rendering does not look as it should, but because height maps are actually used in the wrong situation.

As an improvement, the pixels of a high-altitude map can be stored in a 16-bit floating number (half float) or 32-bit floating, which allows you to have higher ranges and accuracy, resolved with an 8-bit pixel with a fixed accuracy.